Activity: Population – More is Less



Activity: Population – More is Less

Background Information

What is the most pressing environmental issue of our time? Is it acid rain? Air pollution? Deforestation? While some authorities might answer differently, most would agree that the problem of human population growth is of major importance.

To see why this is so, we need to consider two aspects of human population growth: the quantity of human life and the quality of human life. First let us consider the quantity of human life.

Population growth occurs when the number of organisms entering a population exceeds the number of organisms leaving it. The population of a city, for example, grows if the people moving into it (immigration) plus the number of people born in it is greater than the sum of the number of people moving out (emigration) and the number of deaths. When considering the Earth, we need to consider the birth rate (number of live births per 1,000 people in a year) as compared to the death rate (number of deaths per 1,000 people per year).

For most of human existence, the death rate nearly equaled the birth rate, and the population grew very slowly. It took perhaps 2 billion years for the human population to reach 1 billion, around the year 1810. It took only 117 more years to add the second billion (1927), only 33 years to add the third billion (1960), 14 years to add the fourth billion (1974), and only 13 more years to reach 5 billion in 1987. As of 2009 the world population is 6,789,213,560 people. It is predicted that the Earth’s population will reach 9 billion people by 2040 and 13 billion by 2067. This type of growth is called “exponential growth”. Part 2 of this activity will allow you to investigate exponential growth.

As you do Part 2, keep the following current growth rates in mind:

The World = 1.2% per year

United States: 0.97% per year

Mexico = 1.12% per year

Europe = 0.3%

Afghanistan = 4.8%

Canada = 0.9%

Africa = 2.9%

Asia = 1.9%

Latin America = 2.1%

Increased population growth generally represents problems for a country - it means increased need for food, infrastructure, and services. These are expenses that most high-growth countries have little ability to provide today, let alone if population rises dramatically.

Those who study populations, demographers, often consider the doubling time for a population. We can see that the population of Earth doubled between 1960 and 2009, a doubling time of only 49 years! Compare this to the 117 years that it took to double from 1 billion in 1810 to 2 billion in 1927, and the 47 years that it took to double again to 4 billion!

Any place on Earth can support only certain numbers of any type of organism, including humans. This is called the carrying capacity. The human population growth curve is currently following an exponential curve. Common sense tells us that such growth cannot continue - otherwise within a few hundred years every square foot of the Earth's surface would be taken up by a human. Furthermore, experience with other species tells us that, ultimately, resource limitations and/or habitat degradation will force the human population curves to approach an upper limit or the carrying capacity. It is very natural to ask the linked questions - does humanity have a carrying capacity and, if so, what is it - and when will we reach or overshoot this limit? Some demographers feel that we have already exceeded it. Others think that our ability to manipulate our environment will enable us to support even more people. Regardless of how many people can possibly exist on Earth, how many of us should there be? Is our goal to have as many people as possible existing on Earth, or is our goal for people to have happy, healthy, fulfilling lives?

The United States has about 4.3% of the world’s population but uses about 30% of the resources that are consumed each year. Is it possible for all people to achieve the standard of living that we in the United States now enjoy? Is it possible for the United States and other developed countries to continue consuming at their current rates? As individuals we need to start asking ourselves these questions and taking a hard look at the unsettling answers.

Activity: Population – More is Less

Part 1

Directions:

• Read the Background Information page located on your desk. (Class set)

• Answer the following questions…

1. What is the most pressing environmental issue of our time?

2. What two aspects of population growth do we need to consider when discussing this issue?

3. When does population growth occur?

4. Describe the following:

a. Immigration: ___________________________________________________________

b. Emigration: ____________________________________________________________

c. Birth rate: _____________________________________________________________

d. Death rate: _____________________________________________________________

5. How long did it take the human population to reach 1 billion people?

6. How long did it take the human population to go from 4 billion people to 5 billion people?

7. a. What is the current growth rate of the World?

b. What is the current growth rate of the United States?

c. What is the current growth rate of Afghanistan?

8. What are some problems associated with increased population growth?

9. What name is given to those who study populations?

10. What does the term “carrying capacity” mean?

11. What type of population growth is the World currently following?

12. What will eventually slow the population growth of the World as it reaches its carrying capacity?

13. Even though the United States only hosts 4.3% of the World’s population how much of the World’s resources does the United States use?

Part 2

Directions:

• Construct a line graph comparing a Linear Growth Rate of 1% to an Exponential Growth Rate of 3%.

• Label the X-axis in Years (1 - 20)

• Label the Y-axis in Population Count. Use increments of 2 starting at 100. (100 – 176)

• Graph the Linear Growth rate data using the color GREEN.

• Graph the Exponential Growth rate data using the color RED.

• Put a title on your graph & Make a Key for your graph

|Linear Growth Rate of 1% |

|Year |Population Count | |Year |Population Count |

|1 |100 | |11 |112 |

|2 |102 | |12 |113 |

|3 |103 | |13 |114 |

|4 |104 | |14 |115 |

|5 |105 | |15 |116 |

|6 |106 | |16 |117 |

|7 |107 | |17 |118 |

|8 |108 | |18 |120 |

|9 |109 | |19 |121 |

|10 |110 | |20 |122 |

|Exponential Growth Rate of 3% |

|Year |Population Count | |Year |Population Count |

|1 |100 | |11 |134 |

|2 |103 | |12 |138 |

|3 |106 | |13 |143 |

|4 |109 | |14 |147 |

|5 |113 | |15 |151 |

|6 |116 | |16 |156 |

|7 |119 | |17 |160 |

|8 |123 | |18 |165 |

|9 |127 | |19 |170 |

|10 |130 | |20 |175 |

Part 3

Directions:

• Decide whether each item is generally “good” for people and the environment or is generally “harmful” for people and the environment.

• If it is “good”, place a GREEN “+” in the space beside the item

• If it is “harmful”, place a RED “-“ in the space beside the item

Clean water ______

Energy ______

Noise ______

Buildings ______

Overgrazing ______

Hunger ______

Material luxuries ______

Polluted air ______

Minerals ______

Space to live ______

Cars & Roads ______

Unemployment ______

Soil erosion ______

Forests ______

Food ______

Wildlife ______

Acid Rain ______

Garbage ______

Poverty ______

Oil spills _____

Crowded cities ______

Opportunities for solitude ______

Endangered species ______

Contagious disease ______

Traffic congestion ______

Available housing ______

International conflicts ______

Recreational space ______

Part 4

Directions:

• Now consider the effect of a significantly increased human population on each item from Part 3.

• If increasing the human population would tend to increase the item, write the item inside the arrow pointing upward.

• If increasing the human population would tend to decrease the item, write the item inside the arrow pointing downward.

• Use a GREEN writing tool for the “good” things - **See part 3

• Use a RED writing tool for the “harmful” things - **See part 3

Increases human population tends to Increases human population tends to

increase these items from Part 3: decrease these items from Part 3:

1. a. How many “good” items did you write in the arrow pointing upward (increasing)? ____________

b. How many “harmful” items did you write in the arrow pointing upward (increasing)? ____________

2. a. What trend did you see in the amount of “good” items continuing if there is a significant increase in

human population?

b. Is this trend a positive or negative thing for the human population? Explain.

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